The present invention is related to a cutting rubber assembly which requires low maintenance and which can be used in machines that cut webs of any sort.
U.S. Pat. No. 5,107,733 is related to an apparatus for cutting and transporting a paper web in a folding apparatus of a printing press. An apparatus for transporting a web in a printing press comprises a pair of cutting cylinders for cutting web sections from the web, and a transporting device for transporting the web sections away from the cutting cylinders. The first cutting cylinder has at least one cutting angle and the second cutting cylinder has at least one cutting knife which meets the cutting angle at a nip between the cutting cylinders, to cut the web moving through the nip. A plurality of strips are supported on the first cutting cylinder and a plurality of strips are supported on the second cutting cylinder. The strips have positioned on the cutting cylinders in which they impress a temporary reinforcing profile onto each newly formed leading portion of the web, when the strips move through the nip. At least one smoothing surface is supported on the first cutting cylinder and at least one smoothing surface is supported on the second cutting cylinder. The smoothing surfaces have positions on the cutting cylinders, wherein the smoothing surfaces remove the temporary reinforcing profile from the leading portion of the web, when the smoothing surfaces move through the nip.
U.S. Pat. No. 5,186,444 concerns a method and device for assuring orderly web travel in a folder by punching holes in a paper width direction.
A method of assuring orderly web travel in a folder includes stamping out of a layer structure formed of mutually superimposed web surface portions, along respective strips thereof, a plurality of tongue-like elements remaining appendant to the web surface portions and projecting through respective holes simultaneously stand out of the web surface portions, so as thereby to hold the web surface portions together at the respective strips thereof and a device for performing the method.
The known devices according to the prior art have anvil bars which are assigned to lateral grooves of the anvil cylinders. Once said anvil bars consisting essentially of rubber are worn out, they have to be exchanged. Maintenance regarding the exchange of anvil bars on cutting cylinders requires considerable down time of the press. Further, the accessibility of said anvil bars is difficult.
A further disadvantage of the rectangular shaped anvil bars known from the art is that they constrain the signature on impact of the knife and cheekwood of the assembly upon the cutting operation only. Prior to and after the cut operation a signature constraint cannot be achieved with device known from the art.
In view of the prior art cited it is an object of the present invention to reduce the maintenance of cutting rubbers.
A further object of the present invention is to improve the constraint on the signature as it is created.
According to the present invention, an apparatus for cutting webs of material includes:
a cutting cylinder having at least one knife assembly assigned to its circumference,
a supporting element assigned to said cutting cylinder forming a cutting region there between, and
a transport belt having integrated cut rubber portions, said transport belt being assigned to said supporting element.
The present invention offers the advantage to index said belt upon wear of the cut rubber spot to a fresh cut rubber spot or portion, respectively. When there are no more fresh spots, the entire belt can be replaced very easily. Furthermore, a constraint is exerted upon the incoming web and the signature resulting there from over the entire length of the cutting region, prior to the cutting region and behind the cutting region.
According to further details of the present invention, said transport belt travels along an endless loop about said supporting element which may be designed as an anvil cut roller or cylinder with a smooth surface. Said revolving transport belt co-operates with an upper web transport device prior to the cutting region as well as with a lower signature transport device. Said transport belt is substantially supported by a supporting element within said cutting region, i. e. upon its section of the travel path opposite said knife cylinder. Said transport belt having cut rubber portions assigned thereto, bridges the distance between said upper web transport device and said lower signature transport device. The width of said transport belt corresponds to the maximum width of the web to be processed in a folder apparatus arranged behind a rotary printing press.
On the transport belt a laminated cut rubber layer may be provided, the cut rubber layer traveling with the transport belt about its closed loop. Upon wearing of a spot of the laminated cut rubber layer, the transport belt is indexed, so that a new spot of the respective cut rubber layer co-operates with respective knife assemblies upon a cutting operation. As an alternative, distinct cut rubber portions may be integrated into the transport belt received in lateral grooves assigned to said transport belt. Upon the occurrence of a cut operation, said spot of the cut rubber layer or said distinct cut rubber portions received by a lateral groove are supported by said supporting element, being an anvil roller having a smooth surface for instance.
Along the entire surface of said transport belt adjacent cut rubber portions may be arranged so as to provide several fresh cutting anvils which are easy to replace upon wear.
The present invention further discloses a method for severing signatures from an incoming web of material comprising the steps of
constraining an incoming web of material between a transport belt and a signature transport device,
supporting said transport belt having cut rubber portions integrated therein by a supporting element upon impact of a knife assembly, and
constraining the severed signature between a portion of said transport belt and a signature transport device upon further travel of the severed signature in signature travel direction.